Power amplifier with provisions for varying operating voltage based upon power amplifier output power

ABSTRACT

A power amplifier system is disclosed in which a power amplifier unit and a power amendment unit are provided. An operating voltage is applied to the power amplifier unit. The power management unit monitors the current drawn by the power amplifier unit and generates a control signal based upon the measured current. The operating voltage applied to the power amplifier unit is adjusted based upon the control signal.

CLAIM OF PRIORITY

[0001] This application claims priority to co-pending U.S. provisionalapplication entitled, “A POWER AMPLIFYING SYSTEM,” having Ser. No.60/184,682, filed Feb. 24, 2000, which is entirely incorporated byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention is generally related to power amplifiers and, moreparticularly, to a system for increasing overall efficiency of a poweramplifier by varying operating voltage applied to a power amplifierbased upon the output power level of the power amplifier.

[0004] 2. Related Art

[0005] In personal communications devices such as cellular telephones,there is a trend toward minimizing size and weight. The size and weightare, however, contingent upon the size and weight of the variouscomponents that make up the personal communications device. In short,the smaller the various components of the personal communicationsdevices, the smaller the size and overall weight of the personalcommunications device itself. Many personal communications devices havean overall size and weight which is, to a large degree, dominated by thesize and weight of the battery which provides a supply voltage to thepersonal communications device. This is generally due to the fact thatconsumers want a personal communications device to have a prolongedoperating time during usage.

[0006] As operating time requirements and power consumption of thepersonal communications device during operations increases, the size ofthe battery required to perform under these circumstances will alsoincrease. Thus, where current or power consumption of the personalcommunications devices can be reduced; or the size of components can bereduced; the size of the battery can also be reduced. Alternatively,where the size of the battery remains constant, the operating time ofthe personal communications devices can be increased.

[0007] In typical personal communications devices such as, for example,wireless communication devices, efficiency of the device is optimized atmaximum power output without regard to whether or not maximum poweroutput is actually needed. Thus, as the power output of a typicalwireless communications device, for example, drops below the maximumpower (Max Power) output level, the efficiency of the wirelesscommunications device also drops. This does not help to prolong thesupply battery voltage and thus works to limit the operation time to thedevice.

SUMMARY

[0008] The invention provides a system for improving the efficiency of apower amplifier. Briefly described, in architecture, the system can beimplemented as follows: a power amplifier unit and a power amendmentunit are provided. An operating voltage is applied to the poweramplifier unit. The power management unit monitors the current drawn bythe power amplifier unit and generates a control signal based upon themeasured current. The operating voltage applied to the power amplifierunit is adjusted based upon the control signal. Adjustment to theoperating voltage may be made via the power management unit or via anexternal regulator unit.

[0009] The invention can also be viewed as providing a method forapplying an operating voltage to a power amplifier unit. In this regard,the method can be broadly summarized by the following steps: Anoperating voltage Vbb is applied to a power amplifier unit 120. Thecurrent drawn by the power amplifier unit is then monitored and thecurrent flow is measured. A current flow signal is generated and outputbased upon the measured current flow. The current flow signal is thenreceived by a controller that generates a control signal based upon thecurrent flow signal. The control signal is then output to a voltageregulator, which then adjusts the operating voltage applied to the poweramplifier unit based upon the control signal.

[0010] Other systems, methods, features, and advantages of the inventionwill be or become apparent to one with skill in the art upon examinationof the following figures and detailed description. It is intended thatall such additional systems, methods, features, and advantages beincluded within this description, be within the scope of the invention,and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The components in the drawings are not necessarily to scale,emphasis instead being placed upon clearly illustrating the principlesof the invention. In the figures, like reference numerals designatecorresponding parts throughout the different views.

[0012]FIG. 1 is a block diagram illustrating a power amplifier controlsystem.

[0013]FIG. 2 is a block diagram illustrating another embodiment of apower amplifier control system.

[0014]FIG. 3 is a block diagram illustrating a bypass unit 190.

[0015]FIG. 4 is a block diagram illustrating another embodiment of apower amplifier control system.

[0016]FIG. 5 is a block diagram illustrating the power amplifier controlsystem in FIG. 1.

[0017]FIG. 6 is diagram detailing one configuration for determiningpower amplifier unit power consumption.

[0018]FIG. 7 is a further diagram detailing a configuration fordetermining power amplifier unit power consumption.

[0019]FIG. 8 is a flowchart illustrating a method of applying anoperating voltage to a power amplifier unit of a personal communicationsdevice.

[0020]FIG. 9 is a block diagram illustrating a look up table (“LUT”) forcorrelating current flow values with control signal values.

[0021]FIG. 10 is a flowchart illustrating another method of applying anoperating voltage to a power amplifier unit of a personal communicationsdevice.

DETAILED DESCRIPTION

[0022] The personal communications device of the invention provides forreduced power consumption by varying the operating voltage that isapplied to the circuitry of the personal communications device. Moreparticularly, the operating voltage applied to the power amplificationunit of the personal communications device is varied based upon themeasured output power level of power amplifier.

[0023]FIG. 1 illustrates one embodiment of a personal communicationsdevice 100. A power amplifier unit 120 and power management unit 110 areprovided. Power amplifier unit 120 includes a power amplifier 150. Poweramplifier 150 includes an input 151 for receiving a radio frequency (RF)signal and an output 152 for outputting an amplified RF signal.

[0024] Power management unit 110 includes a current meter 180, acontroller 170 and a regulator 160. An operating voltage Vbb is providedto the power amplifier 150 by voltage regulator 160. Switching regulator160 receives a supply voltage Vcc of a predetermined voltage level andoutputs an operating voltage Vbb to the power amplifier 150.

[0025] A current meter 180 monitors (measures) the DC current flow ofthe operating voltage supply Vbb provided to the power amplifier unit120 and generates a current flow indicator signal X representative ofthe measured DC current flow of the operating voltage supply applied tothe power amplifier unit 120. This current flow indicator signal X isprovided to a controller 170. By monitoring the current Ibb drawn by thepower amplifier unit 120, it is possible to determine the power outputof the power amplifier unit 120. In this way, for a given current flowindicator signal X, there is a corresponding output power level at whichthe power amplifier unit 120 operates. By monitoring the current Ibbdrawn by the power amplifier unit 120, it is possible to determine thepower output of the power amplifier unit 120. In this way, the currentsignal X can also be considered indicative of the power output level ofthe power amplifier unit 120.

[0026] Controller 170 controls switching regulator 160 via providing acontrol signal Z. Control signal Z is generated by the controller 170based upon the current flow indicated by the current flow indicatorsignal X.

[0027] The operating voltage Vbb output by the regulator 160 to thepower amplifier 150 is determined in accordance with the control signalZ output by controller 170.

[0028] The operating voltage Vbb may be selected from any one of apredetermined number of voltage levels. For example, Vbb may be between0 volts and the supply voltage Vcc. Further, Vbb may be linearlyvariable between, for example, 0 volts and Vcc, in accordance with thecontrol signal Z.

[0029]FIG. 2 shows a block diagram illustrating a power amplifiercontrol system. A power amplifier unit 120 is provided and includes apower amplifier 150. Power amplifier 150 includes an input 151 forreceiving a radio frequency (RF) signal and an output 152 for outputtingan amplified RF signal.

[0030] A power management unit 110 is provided. Power management unit110 includes a power meter 180, a controller 170, a regulator 160 and abypass switch 190. The output 152 of power amplifier 150 is connected toa power meter 180.

[0031] Power meter 180 monitors (measures) the power at the output ofthe power amplifier 152 of power amplifier 150 and generates a poweroutput indicator signal X.

[0032] This power output indicator signal X is then provided to thecontroller 170. Controller 170 receives the signal X and in turn,generates a control signal Z and a bypass signal Z′. Control signal Zvaries depending upon the value of the power output indicator signal X.Control signal Z′ also varies depending upon the value of the poweroutput indicator signal X. Controller 170 controls regulator 160 viaproviding a control signal Z.

[0033] Regulator 160 receives a supply voltage Vcc of a predeterminedvoltage level and outputs an operating voltage Vbb to the poweramplifier 150. The operating voltage Vbb output to the power amplifier150 is determined in accordance with the control signal Z and bypasssignal Z′ output by controller 170. The operating voltage Vbb may be anyone of a predetermined number of voltage levels between, for example, 0volts and Vcc. Further, the operating voltage Vbb may be linearlyvariable between, for example, 0 volts and Vcc, in accordance with thecontrol signal Z. In a preferred embodiment, the regulator 160 outputs aoperating voltage Vbb, to the power amplifier unit 120, of approximately2.2 volts (+2.2 VDC) where the power output indicator signal X indicatesthat the power amplifier unit 120 is operating at a power level of lessthan, for example, 22 dBM.

[0034] Bypass switch 190 is connected in parallel with the regulator 160and receives input of the supply voltage Vcc. Bypass switch 190 iscontrolled by bypass signal Z′, that causes the bypass switch 190 toopen or close. When bypass switch 190 is closed, the operating voltageVbb applied to the power amplifier unit 120 preferably goes to theoperating supply voltage Vcc. In a preferred embodiment, bypass switch190 is closed when the power output indicator signal X indicates thatthe power amplifier unit 120 is consuming, or operating at, a high powerlevel. For example, where the power amplifier unit is consuming a powerlevel greater than 22-24 dBm, the bypass signal Z′ may be output by thecontroller 170 to close the bypass switch 190. Once bypass switch 190 isclosed, the operating voltage Vbb applied to the power amplifier unit120 is effectively taken to a level approximately equal to the supplyvoltage Vcc.

[0035]FIG. 3 is a more detailed illustration of bypass unit 190. It canbe seen that bypass unit 190 includes a switch 302 that is actuated bythe bypass signal Z′. Bypass unit 190 may be configured, for example, byusing transistor (semiconductor) switches for switch 302. Further,bypass unit 190 may be configured using electrically actuated mechanicalswitching devices as switch 302.

[0036]FIG. 4 is a block diagram illustrating another embodiment of apower amplifier control system. A power amplifier unit 120 and powermanagement unit 110 are provided. Power amplifier unit 120 includes apower amplifier 150. Power amplifier 150 includes an input 151 forreceiving a radio frequency (RF) signal and an output 152 for outputtingan amplified RF signal

[0037] In addition, the power amplifier 150 of power amplifier unit 120may provide for enable input (enable pin) 453 that is capable of turningon and off the power amplifier 150 by application of a predeterminedsignal. This signal may be, for example, a complementary metal oxide(CMOS) or transistor transistor logic (TTL) compliant/compatible signal.The power amplifier unit 120 may also provide for a reference voltageinput (reference voltage pin) 454, which may be used to provide areference voltage Vref to control the operation of the power amplifier150. The reference voltage Vref may also be used to sense the outputpower of the power amplifier unit 120.

[0038] Power management unit 110 includes a current meter 180, acontroller 170, a bypass switch 190, and a reference voltage regulator165. An operating voltage Vbb is provided to the power amplifier 150 byvoltage supply regulator 160. An operating voltage, Vref is supplied tothe power amplifier 150 by the reference voltage regulator 165. Currentmeter 180 monitors the current flow of the line providing the referencevoltage Vref from the reference voltage regulator to the power amplifier150 and generates a current indicator signal X that is applied to thecontroller 170. In turn, controller 170 outputs a control signal Z tothe voltage regulator 160. Voltage regulator 160 receives a supplyvoltage Vcc of a predetermined voltage level and outputs an operatingvoltage Vbb to the power amplifier 150 in accordance with the controlsignal Z received from the controller 170.

[0039] The current meter 180 monitors (measures) the DC current flow ofthe reference voltage supply Vref provided to the power amplifier unit120 and generates a current flow indicator signal X representative ofthe measured DC current flow of the operating voltage supply applied tothe power amplifier unit 120. This current flow indicator signal X isprovided to a controller 170. By monitoring the current Ivr drawn by thepower amplifier unit 120, it is possible to determine the power outputof the power amplifier unit 120. In this way, for a given current flowindicator signal X, there is a corresponding output power level at whichthe power amplifier unit 120 operates. By monitoring the current Ivrdrawn by the power amplifier unit 120, it is possible to determine thepower output of the power amplifier unit 120. In this way, the currentsignal X can also be considered indicative of the power output level ofthe power amplifier unit 120.

[0040] In one embodiment, controller 170 controls switching regulator160 via control signal Z. Control signal Z may be generated by thecontroller 170 based upon the current flow indicated by the current flowindicator signal X.

[0041] The operating voltage Vbb output by the voltage regulator 160 tothe power amplifier 150 is determined in accordance with the controlsignal Z output by controller 170. The operating voltage Vbb may beselected from any one of a predetermined number of voltage levels. Vbbmay be between, for example, 0 volts and the supply voltage, Vcc.Further, Vbb may be linearly variable between, for example, 0 volts andVcc, in accordance with the control signal Z. In a further embodiment,an external control signal M may be applied to the controller 170. Inturn, the controller 170 generates the control signal Z in accordancewith the external control signal M. Control signal M may be, forexample, a logic signal generated by an external source associated withthe system 100.

[0042]FIG. 5 shows a block diagram illustrating the power amplifiercontrol system in FIG. 1. In this example, power amplifier unit 120 is amulti-stage power amplifier unit. Power amplifier unit 120 includes aninput matching unit 552 for matching the impedance of the input 151 to apower amplifier 554. The output of power amplifier 554 is connected toan interstage matching unit 556. Interstage matching unit 556 matchesthe output impedance of power amplifier 554 to the input impedance ofpower amplifier 558. An output matching unit 560 is provided to matchthe output impedance of power amplifier 558 to the output 152. The biascontrol network 520 is capable of powering on (enabling) the amplifierunit 120 by using the reference current Ivr from the power managementcircuit 110 or by applying an appropriate enable signal to an enable pin553 that may be optionally provided. Bias control 520 is preferablyconfigured as a part of the power amplifier unit 120.

[0043] Power management unit 110 includes a current meter 180 andcontroller 170. Current meter 580 measures the current Ibb drawn by thepower amplifier unit 120. A current signal X is generated to indicatethe current Ibb drawn by the power amplifier unit 120.

[0044] Alternatively, current meter 580 may be configured to measure thecurrent Ivr drawn by the power amplifier unit 120 as shown in FIG. 6. Inthis case, a current signal X is generated to indicate the current Ivrdrawn by the power amplifier unit 120.

[0045] For a given current flow indicator signal X, there is acorresponding output power level at which the power amplifier unit 120operates. By monitoring the current Ibb drawn by the power amplifierunit 120, it is possible to determine the power output of the poweramplifier unit 120. In this way, the current flow indicator signal X canalso be considered indicative of the power output level of the poweramplifier unit 120.

[0046] The current flow indicator signal X is provided to the controller170. Controller 170 receives the current flow indicator signal X and inturn, generates a control signal Z and bypass signal Z′. Control signalZ and bypass signal Z′ varies depending upon the value of the currentflow indicator signal X. This control signal Z and the bypass signal Z′are each applied to the base of field effect transistors (FET) 568 and570, respectively. FET 570 is controlled by control signal Z and isconnected between the supply voltage Vcc and an inductor 365. FET 570 iscontrolled by bypass signal Z′ and is connected between the supplyvoltage Vcc and the output of the inductor 565. The control signal Zcauses the FET 568 to adjust current flow through the inductor 565 andin turn causes the operating voltage Vbb to be adjusted upward ordownward as required. The control signal Z′ causes the FET 570 to turnon completely so as to provide supply voltage Vcc directly to the poweramplifier unit 120, thus greatly reducing the power losses between Vccand the power amplifier unit 120 under high current operation.

[0047] Controller 170 also provides a reference voltage Vref to the biascontroller 520. The reference voltage Vref is preferably independent ofthe operating voltage Vbb. In a preferred embodiment, reference voltageVref is three volts (+3.0 VDC).

[0048] In one embodiment of the personal communications device 100, theoperating voltage Vbb is, for example, between +3.0 and 4.2 volts DC(+3.0 VDC-+4.2 VDC). Further, where the current monitor 180 detects acurrent flow Ibb that corresponds to an amplifier power output of onemilliwatt (1 mW), the controller 170 outputs a control signal Z andbypass signal Z′ that causes the operating voltage Vbb to be adjusted to+0.6 volts DC (+0.6 VDC), thus greatly increasing the efficiency of thepower amplifier unit 120.

[0049] The power amplifier unit 120 may be fabricated using galliumarsenide (GaAs) semiconductor technology. The power management unit 110may also be fabricated using complementary metal oxide semiconductor(CMOS) technology. Further, both power amplifier unit 120 and powermanagement unit 110 may be fabricated on a single integrated circuit.The integrated circuit may be configured in a package having a lengthof, for example, but not limited to, between 8.25-8.51 millimeters (mm);and a width of between 8.26-8.51 millimeters(mm). Alternatively, poweramplifier unit 120 and power management unit 110 may be fabricated onseparate integrated circuits.

[0050]FIG. 7 shows a block diagram illustrating another embodiment of apower amplifier control system. In this embodiment, a regulator 160 isprovided to supply the power amplifier unit 120 with an operatingvoltage Vbb. In this embodiment regulator 160 is external to the powermanagement unit 110 and is controlled by a control signal Z from thecontroller 170. This embodiment provides for a personal communicationsdevice 100 in which the power amplifier unit 120 and power managementunit 110 may be configured on a single integrated circuit, as discussedabove with regard to FIG. 4, and utilized in conjunction with a separatevoltage regulator. Voltage regulator 160 may be, for example, aswitching voltage regulator.

[0051]FIG. 8 is a flowchart illustrating a method of providing anoperating voltage to a power amplifier unit. An operating voltage Vbb isapplied to the power amplifier unit 120 (802). The current drawn by thepower amplifier unit 120 is then monitored by, for example, a currentmeter 180, to measure the current flow Ibb (or, alternatively, thecurrent flow Ivr) (804). A current flow signal is generated by thecurrent meter 180 and output to a controller 170 based upon the measuredcurrent flow (806). The current flow signal is then received by acontroller 170 that then generates a control signal based upon thecurrent flow signal (808). The control signal is then output to aregulator 160 that then adjusts the operating voltage applied to thepower amplifier unit 120 based upon the control signal (810).

[0052]FIG. 9 illustrates an embodiment of a personal communicationsdevice in which a lookup table (LUT) 910 is incorporated and utilizedfor correlating a measured current value with a corresponding controlvalue (control signal value). LUT 910 may be incorporated as a part ofthe power management unit 110. Alternatively, it may be external to thepower management unit 110. A power amplifier unit 120 and powermanagement unit 110 are provided. Power amplifier unit 120 includes apower amplifier 150. Power amplifier 150 includes an input 151 forreceiving a radio frequency (RF) signal and an output 152 for outputtingan amplified RF signal.

[0053] Power management unit 110 includes a current meter 180, acontroller 170 and a regulator 160. An operating voltage Vbb is providedto the power amplifier 150 by voltage regulator 160. Regulator 160receives a supply voltage Vcc of a predetermined voltage level andoutputs an operating voltage Vbb to the power amplifier 150.

[0054] A current meter 180 monitors (measures) the DC current flow Ibbof the operating voltage supply Vbb provided to the power amplifier unit120 and generates a current flow indicator signal X representative ofthe measured DC current flow of the operating voltage supply applied tothe power amplifier unit 120. This current flow indicator signal X isprovided to a controller 170. Controller 170 accesses and refers to theLUT 910 to obtain a control signal value corresponding to the currentflow indicator signal X. The control signal value Z is then output tothe regulator 160. In turn regulator 160 adjusts the operating voltageVbb output by the regulator 160 and applied to the power amplifier unit120 based upon the control signal Z value retrieved from LUT 910.

[0055] The operating voltage Vbb may be selected from any one of apredetermined number of voltage levels. Vbb may be between, for example,0 volts and the supply voltage, Vcc. Further, Vbb may be linearlyvariable between, for example, 0 volts and Vcc, in accordance with thecontrol signal Z.

[0056]FIG. 10 is a flowchart illustrating a further method of providingan operating voltage to a power amplifier unit. It can be seen that anoperating voltage Vbb is applied to the power amplifier unit 120 (1002).The current drawn by the power amplifier unit 120 is then monitored by,for example, a current meter 180, to measure the current flow Ibb (or,alternatively, the current flow Ivr) (1004). A current Row signal isgenerated by the current meter 180 and output to a controller 170 basedupon the measured current flow (1006). The controller 170 refers to alook up table (LUT) to determine a value that corresponds to themeasured current flow (1008). The controller 170 that then outputs acontrol signal based upon the corresponding value (1010). The controlsignal is then output to a regulator 160 that then adjusts the operatingvoltage applied to the power amplifier unit 120 based upon the controlsignal (1012).

[0057] The flow charts of FIG. 8 and FIG. 10 show the architecture,functionality, and operation of a possible implementation of thesoftware capable of carrying out the methodology set out therein. Inthis regard, each block represents a module, segment, or portion ofcode, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat in some alternative implementations, the functions noted in theblocks may occur out of the order noted in the flowcharts of FIG. 8 andFIG. 10. For example, two blocks shown in succession in the flowchartsmay in fact be executed substantially concurrently or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved.

[0058] While various embodiments of the invention have been described,it will be apparent to those of ordinary skill in the art that many moreembodiments and implementations are possible that are within the scopeof this invention.

What is claimed:
 1. A personal communications device comprising: a poweramplifier for receiving an input signal and outputting an amplifiedsignal; battery interface for receiving a supply voltage from a batterypower source; and controller for varying the supply voltage provided tothe power amplifier in accordance with the power consumption of thepower amplifier.
 2. A power amplifier comprising: amplifier stage forreceiving an input signal and outputting an amplified signal; batteryinterface for receiving a supply voltage and providing the supplyvoltage to the amplifier stage; and controller for varying the supplyvoltage provided to the amplifier stage in accordance with the powerconsumption of the amplifier stage.
 3. The power amplifier of claim 2,further comprising a power monitor for monitoring the power consumed bythe amplifier stage.
 4. The power amplifier of claim 3, wherein thecontroller varies the supply voltage in accordance with a signal fromthe power monitor.
 5. A power amplifier according to claim 3, furthercomprising a look-up table (LUT) which specifies a predetermined supplyvoltage level for a given current level.
 6. A power amplifier accordingto claim 5, wherein the controller causes the supply voltage to bevaried in accordance with the look up table and the current level signalfrom the current meter.
 7. A power amplifier according to claim 2,wherein the supply voltage is varied linearly in relation to the powerconsumption of the amplifier stage.
 8. A personal communications devicecomprising: a supply input for receiving a power supply voltage; a poweramplifier unit; a controller; a voltage regulator for receiving a powersupply voltage input via the supply input and outputting a operatingvoltage supply to the power amplifier; a current monitor for measuringthe current flow of the operating voltage supply output to the poweramplifier unit and outputting a current indicator signal; the controllerreceives the current indicator signal and generates a control signal inaccordance with the current indicator signal; and the voltage regulatoradjusts the operating voltage supply in accordance with the controlsignal.
 9. The personal communications device of claim 2, wherein thepower amplifier unit comprises a two stage power amplifier.
 10. Thepersonal communications device of claim 2, further comprising a mobiletelephone.
 11. The personal communications device of claim 4, whereinthe mobile telephone comprises a code division multiple access (CDMA)compliant mobile telephone.
 12. The personal communications device ofclaim 4, wherein the mobile telephone comprises a time division multipleaccess (TDMA) compliant mobile telephone.
 13. A personal communicationsdevice comprising: a supply input for receiving a power supply voltage;a power amplifier unit; a regulator for receiving a power supply voltageinput via the supply input and outputting a operating voltage supply tothe power amplifier unit; the power amplifier unit further comprises acurrent monitor for measuring the current flow of the operating voltagesupply output to the power amplifier unit and outputting a currentindicator signal in accordance therewith; the power amplifier unitfurther comprises a controller for receiving the current indicatorsignal and generating a control signal in accordance with the currentindicator signal; and the voltage regulator adjusts the operatingvoltage supply in accordance with the control signal.
 14. The personalcommunications device of claim 8, wherein the power amplifier unitcomprises a radio frequency power amplifier.
 15. The personalcommunications device of claim 8, wherein the power amplifier unitcomprises a multi-stage radio frequency power amplifier.
 16. Thepersonal communications device of claim 8, wherein the power amplifierunit comprises an integrated circuit.
 17. The personal communicationsdevice of claim 11, wherein the integrated circuit comprises a galliumarsenide (GaAs) integrated circuit.
 18. A power amplifier unitcomprising: a power amplifier; an input for receiving an operatingsupply voltage to power the power amplifier; a current monitor formonitoring the current flow of the operating supply voltage andoutputting a current flow signal based upon the measured current flow;and controller for outputting a control signal based upon the currentflow signal.
 19. The power amplifier unit of claim 18, wherein the poweramplifier comprises a radio frequency power amplifier.
 20. The poweramplifier unit of claim 19, wherein the power amplifier comprises amulti-stage power amplifier.
 21. The power amplifier unit of claim 18,wherein the power amplifier unit further comprises an integratedcircuit.
 22. The power amplifier unit of claim 18, wherein theintegrated circuit comprises a complementary metal oxide (CMOS)semiconductor.
 23. A power amplifier unit comprising: a power amplifier;an input for receiving a supply voltage; a current monitor formonitoring the current flow of the operating supply voltage andoutputting a current flow signal based upon the measured current flow;controller for outputting a control signal based upon the current flowsignal; and regulator for outputting an operating voltage to the poweramplifier based upon the current flow signal.
 24. The power amplifierunit of claim 18, wherein the power amplifier comprises a radiofrequency power amplifier.
 25. The power amplifier unit of claim 19,wherein the power amplifier comprises a multi-stage power amplifier. 26.The power amplifier unit of claim 18, wherein the power amplifier unitfurther comprises an integrated circuit.
 27. The power amplifier unit ofclaim 21, wherein the power amplifier comprises a gallium arsenide (Gas)transistor.
 28. The power amplifier unit of claim 22, wherein thecontroller comprises a complementary metal oxide (CMOS) transistor. 29.The power amplifier unit of claim 18, wherein the regulator outputs anoperating voltage of +1.6 volts DC where the current flow signalindicates the power amplifier is consuming 1 milliwatt of power.
 30. Apersonal communications device comprising: a power amplifier unit; apower management unit; the power management unit comprises an input forreceiving a supply voltage; a current monitor for monitoring the currentflow of an operating supply voltage applied to the power amplifier unitand outputting a current flow signal based upon the measured currentflow; controller for outputting a control signal based upon the currentflow signal; and regulator for outputting an operating voltage to thepower amplifier unit based upon the current flow signal.
 31. Thepersonal communications device of claim 30, further comprising a bypassunit for selectively providing the supply voltage to the power amplifierunit as the operating voltage.
 32. The personal communications device ofclaim 30, wherein the power amplifier comprises a radio frequency poweramplifier.
 33. The personal communications device of claim 32, whereinthe power amplifier comprises a multi-stage power amplifier.
 34. Thepersonal communications device unit of claim 30, wherein the poweramplifier unit comprises an integrated circuit.
 35. The personalcommunications device unit of claim 34, wherein the integrated circuitcomprises a gallium arsenide transistor.
 36. The personal communicationsdevice of claim 34, wherein the power management unit comprises acomplementary metal oxide (CMOS) transistor.
 37. The personalcommunications device of claim 36, wherein the power management unit andthe power amplifier unit are contained on a single integrated circuit.comprises a complementary metal oxide (CMOS) transistor.
 38. Thepersonal communications device of claim 30, wherein the regulatoroutputs an operating voltage of +1.6 volts DC where the current flowsignal indicates the power amplifier is consuming I milliwatt of power.39. A method of applying a power supply voltage to a power amplifierunit comprising the steps of: applying a operating voltage to a poweramplifier unit; measuring the current drawn by the power amplifier unit;generating a current flow signal indicative of the current drawn by thepower amplifier unit; generating a control signal based upon the currentflow signal; and adjusting the operating voltage based upon the controlsignal.
 40. The method of claim 39, further comprising the step ofadjusting the operating voltage to the supply voltage level where thecurrent flow signal indicates the power amplifier unit is operating at apower level greater than 22 dBm.
 41. The method of claim 39, furthercomprising the step of adjusting the operating voltage to +2.2 volts DC(+2.2 VDC) where the current flow signal indicates the power amplifierunit is operating at a power level of less than 22 dBm.
 42. A method ofapplying a power supply voltage to a power amplifier unit comprising thesteps of: applying a operating voltage to a power amplifier unit;measuring the current drawn by the power amplifier unit; generating acurrent flow signal indicative of the current drawn by the poweramplifier unit; looking up a value corresponding to the current flowsignal; generating a control signal based upon the corresponding value;and adjusting the operating voltage based upon the control signal.
 43. Apersonal communications device comprising: a power amplifier means; apower management means; the power management means comprises an inputfor receiving a supply voltage; a means for monitoring the current flowof an operating supply voltage applied to the power amplifier unit andoutputting a current flow signal based upon the measured current flow;means for outputting a control signal based upon the current flowsignal; and means for outputting an operating voltage to the poweramplifier unit based upon the current flow signal.